We get a lot of questions regarding this topic so figured it was time for a MountGuys Blog posting on the topic.
First, the easy ones. TomTom and Magellan. All of their GPS units made in the past few years use a USB charger.
Now, the difficult one. Garmin. It all depends upon which on you guys. The Garmin Nuvi 600, 700 and 800 series all use a proprietary ending that plugs into their cradle. Can you use the USB type directly into the GPS? Garmin does not recommend it but we have found no material effects with doing that. It’s always good to pay attention to the manufacturer though. So we suggest that if you can do it, use the flat charger with the cradle. A few pictures are presented for the Garmin Nuvi 600 700 and 800 series. By the way, the same charging end is used for the Zumo using the car cradle.
What about the rest of the Garmin Nuvi family? They use cables that are USB as well but with proprietary pin settings. Be sure that the cable you purchase is made for a GPS otherwise you risk going into the dreaded PC mode. Another important tip: many of the cables made for GPS units with traffic can integrate the traffic receiver with the cable itself, so be sure that the cable you buy is rated for traffic if you choose to retain that feature.
Last one. Magellan. They use USB cables with proprietary pin settings too. Ask us any questions you might have about powering up your GPS at firstname.lastname@example.org.